Locating previously purchased ebook for Adobe Digital Editions

I purchased a book years ago which had to be read on Adobe Digital Editions.  I do not know what the book was, only that I still had an old copy of Adobe digital Editions on my computer, migrated over from when I first got it.  How do I restore purchases made for Adobe Digital Editions?  Or could it be anything anywhere, unrelated to the platform "Adobe Digital Editions"?